Final answer:
A brute force attack is a method used in computer science and cybersecurity to crack passwords by trying every possible combination of characters. It only works on weak passwords.
Step-by-step explanation:
The subject of this question is Computers and Technology.
A brute force attack is a method used in computer science and cybersecurity to crack passwords. Option B, which is 'Tries every possible combination of characters to crack a password', accurately describes a brute force attack.
Option D, which is 'Only works on weak passwords', is also correct. Brute force attacks are most effective against weak passwords that can be easily guessed.